Don't be afraid to drizzle the salad dressing

Dressings and oils are assumed to make salads less healthy; however, researchers at Iowa State University found that oil actually helps the body absorb more nutrients from salad vegetables.

Wendy White, lead author of the study and associate professor of food science and human nutrition, studied 12 college-age women who ate salads containing varied levels of soybean oil, a common ingredient in salad dressings. The amount of nutrients absorbed was then measured using blood tests.

Published in the American Journal of Clinical Nutrition, the study found that eating salad with added fat in the form of soybean oil does, in fact, encourage the absorption of eight different micronutrients that aid human health. Health benefits of these nutrients include cancer prevention and eyesight preservation. Consuming the same salad without the oil reduces the likelihood that the body will absorb the nutrients.

These nutrients include four carotenoids — alpha and beta carotene, lutein and lycopene, two forms of vitamin E and vitamin K. The oil also promoted the absorption of vitamin A, the eighth micronutrient which formed in the intestine from the alpha and beta carotene.

White’s team established that there was a proportional relationship between the amount of oil added to the vegetables and the level of nutrient absorption. The participants who consumed 32 g of oil, the largest amount studied, absorbed the most nutrients.

“The best way to explain it would be to say that adding twice the amount of salad dressing leads to twice the nutrient absorption,” White stated.

However, there was some variation between the women, who were chosen for the trial due to differences in the speed with which men and women metabolise nutrients.

“For most people, the oil is going to benefit nutrient absorption,” White said. “The average trend, which was statistically significant, was for increased absorption.”

Therefore, while the study suggests that increasing the volume of oil increases the body’s intake of nutrients, White was careful to suggest that salad eaters should not consume excessive amounts. Instead, following the recommended daily intake in the US of two tablespoons per day should be sufficient.

Worrying about adding a drizzle of dressing to your next salad? Don’t, it’s apparently healthy for you.